import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import java.util.Vector;

public class Test {

	
	public static void main(String[] args) {
		Map<String, String> treeMap = new TreeMap<>();
		
//		treeMap.put(null, null);
		
		System.out.println(treeMap);
		
		
		List<String> arrayList = new ArrayList<>();
		
		arrayList.add(null);
		
		System.out.println(arrayList+" - "+arrayList.size());
	

		List<String> linkedList = new LinkedList<>();
		
		linkedList.add(null);
		System.out.println(linkedList+" - "+linkedList.size());
		

		List<String> vector = new Vector<>();
		
		vector.add(null);
		System.out.println(vector+" - "+vector.size());
	}
}
